Thermic siphon



June l0, 1941- G. J. cl-musTENsoN'y T'HERMIC sIPHoN 2 sheets-sheet 1 Filed Jan. 3, 1939 Jun? l0, 1941- G. J. cHRgs'rENsoN 2,244,675 v THERMIC sIPHoN Filed Jan. s, 1959 y 2 sheets-sheet 2 (n n n u WH' Patented June 10, 1941Y THERMIC SIPHON Gust J. 'Christensom Chicago,.Ill.,`.assignor to Locomotive yFirebox Company, Chicago, .Ill., a v:.zorporation offDclaware Application January 3, 1939, Serial"No.lZ48,977

- 4L Claims.

This invention relates to improvements in thermic siphons and it consists of the matters hereinafter described and more particularly pointed out in the appended claims.

jInv any rebox of lthe locomotive boiler type, there is'some movement of the roof and crown sheets under the temperature and pressure condltions which obtain in use. These movements manifest themselves as deflections or distortions of the sheetsand generally increase with pressure Vand temperature. The 'magnitude of the deflection isalso dependent v-upon the character of the metal employed, i. e. whether of plain carbon steel vor of so-called low alloy, high ten- Sile strength steel.

It is possible to obtain suflcient tensile strengthwith a thinner alloy steel sheet for a given pressure than with a plain carbon steel sheet but deflection in `certain'directions will be greater with the thinner low-alloy high tensile strength `steel than with the relatively thicker, plain carbon steel necessary to provide an adequate or like tensile strength. y

The demand for more power per unit, especially in locomotive boiler practice, has forced the use of higher pressures and larger and longer locomotives. Because of roadway limitations, both as to clearances and as to load supporting capacity, vit is desirable, especially inthe vlarger type locomotives to 'use the thinner sheets of alloy steel rather than the thicker sheets of plain carbon steel. This is true even though the use of'such relatively thin alloy steel sheets'results in `greater movement or deilection of the iirebox sheets which in the larger locomotives is of a relatively high order.

One objectof the present invention is to provide a'thermic Siphon of such constructionl that itis better adapted for use in reboxes, when the size of the'rebox, pressure conditions and the relative thinness of the steel sheets thereof are such as normally to result in a Very considerable movement or deflection of the sheets of the flrebox.

Again, it is an object of the Apresent invention to provide a thermic `Siphon of such construction that it more readily adapts-itself for use in long reboxes of the locomotive Iboiler type and more effectively rigidifles the crown sheet for resisting movement thereof than is possible in siphons as heretofore made.

Another object of 4the invention is toprovide a thermic siphon of lsuch a construction that a longer body may be used and hence greater heat transmission obtained in longer reboxes, without the danger of the movement of the-crown sheet effecting a movement detrimental'to-the top end of the Siphon body.

A further object of the invention is to provide a thermic Siphon structure, which permits of a better support of the non-self supporting `wrapper or roof sheet of the boiler, from the crown sheet, jby making it p possible to 4employ vmore staybolts therebetwee Still another object of the invention is'to-provide a thermic siphon of this'kind wherein it is possible toA impart afbetter forward directional movement to the water discharged Afrom the outlet of the Siphon into the'boiler-water vspace above the crown sheet.

Still a further object of the invention is to provide'a Siphon of this 'kind which is'sofconstructed 'as-to provide `better conditions for working upon staybolts in the crown sheet at apoint between the front and rear ends of the Siphon.

Again, it is a further object of the invention to provide a -siphon having a body which permits of `a lateral movement of the products Ofcombustion through the body of the siphon so as to equalize lamespreading throughout the upper portion of vthe Mirebox, and thus reduce strains due to unequal heating ofA certainl of the 'rebox sheets.

The above mentioned objects of the invention as well as others together with theadfvantages thereof will more `fully appear as the specification proceeds.

In the drawings:

Fig. ll -is a longitudinal vertical sectional View through the frebox end-of a locomotive'bo'iler embodying the preferred formofthe invention.

Fig. 211s a transverse vertical sectional view through the rebox end ofthe boiler as taken on the line 2`2 of Fig.`1.

Fig. 3 is a horizontal detail sectional view 'through the construction Vshown in Fig. '1 as taken on the line 3-'3 of Fig. r1.

Fig. 4 is a'vieW-similar to Fig. 3 but illustrates a modilied form `ofconstruction which will more fully-be described later. Y

Fig. 5 is a fragmentary View in side elevation of `the-upper central portion of a modified form of Siphon structure which -will'be described in more detail later.

Figp is a top plan view of the partsappearing in Fig. 5.

Fig. 7 is a vertical sectional View through that form of the invention appearing in l5 as taken on theline "l-'l of Fig.' 5.

lReferringfnow in detail to l'that lembodiment of the invention illustrated in the accompanying drawings and more especially to Fig. 1 thereof, the flrebox of the locomotive boiler type therein shown and which is a relatively long one, comprises a flue sheet I0, rear sheet II, crown sheet I2 and side sheets I3, the bottom portion of the flue sheet forming the inner throat sheet I4. All of said sheets are arranged in the manner found in iireboxes of this kind. I5 indicates the barrel of the boiler, I6 the top part of the wrapper sheet thereof and I1 and I8 indicate the outer throat sheet and the back sheet thereof respectively.

The sheets I6|1 and I8 coact with the conventional outer side sheets I9 in providing the usual side water legs 20, the front throat 2| and back water leg 22 respectively, all bottomed by a mud ring 23 as appears in Figs. 1 and 2. In the boiler shell are the flues which extend forwardly from the flue sheet toward the usual smoke box. 24 indicates the fuel door opening formed by coacting parts of the sheets Il and I8 respectively. The construction above described, which of course is staybolted in the usual manner may well be taken as typical of that found in boilers of the locomotive type now in general use.

To increase the water steaming and circulating efficiency of such boilers, additional heating elements are'employed in the rebox and such elements usually draw boiler water from a water leg or otherv point toward the bottom of the boiler and discharge the same through the crown sheet. By way of example only, I have illustrated a construction in which the intake is at the front water leg.

In relatively wide freboxes, usually more than one siphon is employed therein and these are spaced apart laterally in the firebox, one on each side of the longitudinal median plane of the boiler and iirebox as a whole as appears in Fig, 2.

In Figs. 1 and 2, the siphon is indicated as a whole by the numeral 25. It comprises a flat hollow body 26 of a somewhat triangular shape, and a tubular inlet neck 21. includes spaced side walls 28-28 (see Fig. 2) front and rear end walls 29 and 39 respectively and a downwardly bulged bottom portion 3l that merges into the neck 21 and is connected by a rounded corner or nose 32 with the rear wall 30. The side walls 28--28 of the body are operatively connected together by the staybolts 28a.. The front and rear walls are inclined downwardly and inwardly and the front wall 29 joins the The siphon body ,j

top rear end portion of the neck 21 by an inside rounded corner or junction 33. It is apparent that a considerable portion of the front end of the body overhangs the neck and this overhang forms a pocket which appears to the right hand side of the vertical line A--A appearing in Fig. 1.

In the upper central portion of the body an opening 34 is formed, which divides the upper or top end of the body into front and rear end outlets 35 and 36 respectively which are spaced apart longitudinally of the body` Each outlet 35--36 as best appears in Figs, 1 and 2 has its own individual flanged top end 31 and 38 respectively and each ilange is fitted and welded in place in a corresponding opening in the crown sheet as indicated at 39 and 40 respectively. The

.front end of the tubular inlet neck 21 engages and is welded in a diaphragm opening 4I in the front throat sheet I4 of the firebox.

It is apparent from Figs. 1 and 2 that the opposite adjacent ends of the lianges 31-38 are spaced apart by a portion of the crown sheet and which portion is indicated by the numeral 42 in Figs. 1 and 3. With such an arrangement it is possible directly to connect and support that part of the wrapper sheet I6 above said crown sheet part 42 with said crown sheet part by means of some of the radial stays 43. Thus the crown sheet is continuous, transversely considered, across the top of the rebox at this point.

If desired, instead of providing a separate flange about the top end of each outlet, a flange 44 common to both outlets 35-36 may be employed, and this arrangement is shown in Fig. 4.

'Ihe opening 34 is of substantially an elongated oval shape, so that its bottom 34a curves upwardly in opposite directions to merge into the rounded ends 34h and 34e respectively and which ends in turn merge into the opposed adjacent ends of the iianges 31--38 The vertical depth of said opening is made of such dimension as to provide sucient room for tools used from inside the rebox, in upsetting those radial staybolts 43 disposed in said crown sheet part 42.

As the water leaves the inner or rear end of the neck 21 and enters the body 26, the curved bottom and the rounded ends of the opening 34 function to deiiect the water and steam bubbles into the respective outlets. The rounded end 34h of said opening also directs or -defiects a part of the water forwardly into the pocket produced by the overhang of the front end of the body as before described. This accelerates circulation of water upwardly along the inner face of the front end of the body to assure sullcient water forwardly of the front outlet in case of low water conditions so that flooding of the higher front end part of the crown sheet is assured even under such adverse conditions.

With the improved siphon construction, when crown sheet movement occurs under service conditions, it is apparent that the use of the longitudinally spaced outlet openings, that are separated by an integral or by a welded in part of the crown sheet, a greater resistance is afforded to the tendency of the transmission of lateral spreading movement of the crown sheet to the top end of the siphon body. Thus tighter connections are afforded for the siphons in the crown sheet, without leakage under service conditions over longer periods of time.

While the arrangement above described may somewhat reduce the area of the outlet opening of the siphon body as a whole and may therefore seem undesirable, the division of the single outlet into a plurality of outlets of lesser area has several advantages which, nevertheless make this arrangement more desirable and practical. Such an arrangement braces the upper central portion of the body against spreading tendency, eliminates the blind or quiescent pocket at the front end of the body by increasing circulation therein and assures suiiicient water forwardly of the siphon to liood the front end of the crown sheet even under low water conditions.

In Figs. 5-6 and 7 I have illustrated a modified form of the invention, which may be embodied in a siphon in the course of its manufacture or by which a long bodied siphon, already in service, may be converted into one embodying the present invention.

In accordance with said modied form of the invention, central portions of both side walls 26a-26a of the body are cut away to form recesses therein, each dened by straight vertical front and rear ends 45 and 46, and an upwardly curved bottom 41 that merges at its ends into rounded corners 48 which in turn merge into said straight vertical ends. In the bottom portion of the recess thus produced, I provide an insert made of two plate-like parts 49-49 each having outer edges, butt welded as at 50 in the major bottom portion of the openings in .the siphon body side walls 26a-25a. The inner edges of the plate-like parts are rounded over toward each other to be welded together as shown at I in Fig. 7.

52 indicates a plate-like crown sheet portion of substantially elongated rectangular form that fits and is welded in an opening providedl therefor in the crown sheet l 2a. The central end portions of this plate-like crown sheet portion are each flanged downwardly as at 53 and these portions each register at the bottom edges with the top end edges of the plates 49. These portions also register at their end edges with that part of the side walls of the siphon body above the top edge of the plates 49. The before-mentioned edges are welded as shown at 54 to those edges with which they have engagement.

It is apparent that the inner ends of the flanges 53 form continuations of the curved portions of the plate members 49 to deilne the top part of the opening 34d. The plates 49--49 are staybolted together as appears in Fig. 5.

The above construction is especially useful in converting a long, single outlet siphon body, ali ready in service, into one with more than one outlet and having the advantages hereinbefore mentioned. v.

While in describing my invention I have referred in detail to the form, arrangement and construction of the parts thereof, the same is to be considered only in the illustrative sense so that I do not wish to be limited thereto exceptl tom portion of the body with the water spacevv in the lower part of the boiler, the front end* wall of the body extending downwardly and inwardly toward the junction of said neck withA4 l' the body, so that the upper front end portion of i the body overhangs a part of said neck, and means forming at least one elongated opening of considerable area through the upper central portion of the body adjacent the crown sheet, said means having its frontv portion so disposed with respect to the before-mentioned junction as to deflect a part of the incoming and upwardly rising water from said junction into the overhanging front end portion "of the body for discharge into the boiler water space above the crown sheet. f

2. In a firebox of the locomotive boiler type having a crown sheet, a longitudinally positioned water wall in the rebox including a mainly flat hollow body, means providing at least one opening of substantial area through the upper central portion of the body adjacent the crown sheet to provide a plurality of longitudinally spaced outlets for said body, which are welded in and open through the crown sheet into the steam and water space of the boiler above said crown sheet, and a tubular inlet neck connecting the bottom portion of the body with the boiler water space in the lower part of the boiler.

3. In a rebox of the locomotive boiler type having a crown sheet, a longitudinally positioned water wall in the rebox including a mainly flat hollow body, means providing at least one opening of substantial area through the upper central portion of the body adjacent the crown sheet, and having a major dimension in the direction of the length of the crownsheet and a minor dimension in a direction substantially perpendicular to the crown sheet, said opening dividing the upper portion of the flat-hollow body into a plurality of longitudinally spacedoutlets therefor which are welded in and-"open through the crown sheet into the steam and Water space of the boiler above said crown sheet, and a tubular inlet neck connecting the bottom portion of the body with the boiler water space in the lower part of the boiler.

4. In a rebox of the locomotive boiler type having a crown sheet with a` plurality of longitudinally extending openings therein separated from each other by a crown sheet portion, a longitudinally positioned water wall in the iirebox including a mainly flat hollow body, there being an opening of substantial area through the upper central portion of the body adjacent the crown sheet to provide a plurality/.of longitudinally spaced outlets for said body, which are welded in said longitudinal openings, said opening in said body being closed at the VJtop by said crown sheet portion, and a tubular inlet neck connecting the bottom portion of the body with the boiler water space in the lowerpart of the boiler.

GUST J. CHRIS'I'ENSON. 

